SUPPLEMENT TOFLIGHT JANUARY 25, 1934
THE AIRCRAFT ENGINEER
surface. The " girth "' becomes flat, but the length re-
mains the same, and is purely a guide to the plating
squad in the shop to locate their plates.
Proceed to mark off on the paper for this drawing
the datum and all the frames or formers to the same
scale as the model, then with a strip of paper girth
round the frames on the model and mark off all plate
edges above and below the datum. Transfer these
marks to the " Shell Expansion Drg." and when all the
plates are drawn in we have a view showing the position
of all plates on one side of the fuselage. Note that any
opening, bracket, etc., only occurring on one side of
the fuselage can still be indicated on the " Half-Block "
model and " Shell Expansion " by labelling same " Stb.
only " or " Port only " as the case may he.
Having transferred all the plates from the half-block
model to the shell expansion and drawn in same, pro-
ceed to label all the strakes as Al, A2, Bl, B2, etc., and
when finished this drawing should be a complete copy
of' the " model " and is used hy the foreman in charge
of the plating as a guide for his work.
Plate Ordering
Last, but not least, the Plate Order List is prepared
from the " model." (See Fig. II.)
Most of the plates amidships can be scaled off direct,
as there is little double curvature, and entered on the
order sheet with a J in. extra in length and J in. extra
in width. Where a plate has double curvature, as at
the nose, place a piece of tracing paper over same and
mark the outline of the plate on the paper. When this
paper is laid out flat we have the true shape of the flat
plate for ordering. This process is called " lifting off.'
When these plates come in from the makers or are cut
from stock, they are labelled as per list, and when all
work is complete thereon they are plated in store, and
as they are marked according to the Shell Expansion
Drg., the foreman in charge of the fuselage plating
knows exactly where each plate goes. It is not sug-
gested here that separate departments should handle
the plates, but one squad does all the rolling and shap-
ing, drilling edges for rivets, etc.
With a reasonable amount of good progress work
beforehand, there should he no waiting one depart-
ment for the other, and when the plates are required
for the final riveting up on fuselage, they should be
ready in store.
Here, perhaps, we should have mentioned that the
" Order List " is prepared first from the model, and
delivered to the ordering department, who, presum-
ably, order same without delay, while the rest of the
work is proceeding. Incidentally, the material for the
frames, etc., is also " lifted off " the model, and a list
made out similar to the plate order list. I have pur-
posely refrained from mentioning the frames previously
as they may he built-up plates with angles, or " Z "
bars, etc., and require a separate drawing for each
frame or batch of frames, but it is obvious that any
information re the contour of the frames can be obtained
from model.
In conclusion, the above procedure for lines, plating,
etc., is applicable to either a " Monocoque Fuselage "
or a flying-boat hull.
it HIDUMINIUM R.R.53 B T
Under the name " Hiduminium R.R.53 B," High
Duty Alloys, Ltd., of Slough, have introduced a new
light aluminium alloy. This is the result of many
months of research work in the laboratories of the firm,
with the object of altering the standard alloys to suit
a particular purpose. The new alloy is a slight modi-
fication of the well-known Hiduminium R.R.53, which
is one of the series of allovs introduced and patented by
Rolls-Royce, Ltd. The new alloy is finding wide applica-
tion for fast-moving levers, treadles and brackets in
the textile and electrical industries, and should also
Some parts cast in Hiduminium R.R.53 B.
be suitable for the smaller forms of castings in the
aircraft industry.
The analysis of Hiduminium R.R. 58 B is as follows :
Copper ... ... 2.5 per cent.
Nickel ... ... 1.5 ,, ,,
Magnesium ... 0.8 ,, ,,
Iron 1.2 ,, ,,
Silicon ... ... 1.2 ,, ,,
The physical properties in the various conditions are as
follows :—
VhM Cast.3 per cent. Maximum
Tn£L T^L Elongation TJrinell
As cast 'Solution'treated
Solution'treated and artificiallyaged
Sand
1
As castSolution treated
Solution treated and artificially
aged
The specific gravity is much th-
in.Tons
8
1223
Cast Text
in. 'Tons
14
22
Burs
per cent. Maximum
XJ 4J ^t.nn.r .0,
Tons/ sq.in.
Tons8
12
li)
e same as fc
Tons/sq "
in.Tons
1217
21
3
6
3
1
)i '' Hiduminium '
75
103
129
^nt. naraiie.- ^
80
110
120
' R.R. 53 alloy
Power and throttle curves of De Havilland " Gipsy Six "
engine. (See pages 84-86.)
78 h